Replace deprecated Buffer constructors with Buffer.from/Buffer.alloc

[and3k5]

new Buffer() has been deprecated for a while now while still being used in the node.js version.

I've replaced the constructor call with their new replacements which is Buffer.from() and Buffer.alloc().

Reference:
https://nodejs.org/docs/latest-v18.x/api/buffer.html

[velkoborsky]

I would also appreciate the merging of this request. It seems straightforward enough and removes an unnecessary ERROR from the logs for many people. It also affects all PDFKit users since it's a dependency of PDFKit.

[velkoborsky]

Replaces deprecated functionality with recommended replacement as described in https://nodejs.org/docs/latest-v18.x/api/buffer.html#new-bufferarray
The replacements are available since Node 4
https://nodejs.org/docs/latest-v4.x/api/buffer.html#buffer_buffer_from_buffer_alloc_and_buffer_allocunsafe